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IE980677A1 - A control system - Google Patents

A control system

Info

Publication number
IE980677A1
IE980677A1 IE980677A IE980677A IE980677A1 IE 980677 A1 IE980677 A1 IE 980677A1 IE 980677 A IE980677 A IE 980677A IE 980677 A IE980677 A IE 980677A IE 980677 A1 IE980677 A1 IE 980677A1
Authority
IE
Ireland
Prior art keywords
linear actuator
hydraulic
fluid line
control system
fluid
Prior art date
Application number
IE980677A
Inventor
William Murray
Peter Miller
James Loeber
Edward Duthie
Original Assignee
Millers Mechanical Nz Ltd Port
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Millers Mechanical Nz Ltd Port filed Critical Millers Mechanical Nz Ltd Port
Publication of IE980677A1 publication Critical patent/IE980677A1/en

Links

Classifications

    • A—HUMAN NECESSITIES
    • A22—BUTCHERING; MEAT TREATMENT; PROCESSING POULTRY OR FISH
    • A22B—SLAUGHTERING
    • A22B5/00—Accessories for use during or after slaughtering
    • A22B5/16—Skinning instruments or knives
    • A22B5/161—Methods or means for pulling the hide from carcasses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/028—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/212—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/421—Flow control characterised by the type of actuation mechanically
    • F15B2211/423—Flow control characterised by the type of actuation mechanically manually, e.g. by using a lever or pedal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5158—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and an output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/625—Accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/75—Control of speed of the output member

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

A control system for controlling the speed of operation of an hydraulic linear actuator. The control system has an hydraulic accumulator coupled via a fluid line (14) and a direction control valve (15) to the hydraulic supply line (13) coupled to the linear actuator (10). Upon the linear actuator experiencing an increased load, hydraulic fluid diverted from the fluid (13) along fluid line (14) accumulates in the accumulator (16) thereby resulting in slower speed of operation of the linear actuator. At low load conditions hydraulic fluid flows from the accumulator (16) into fluid line (13) to increase the speed of operation of the linear actuator. <Fig. 1>.

Description

A CONTROL SYSTEM BACKGROUND OF THE INVENTION This invention relates to a control system.
More particularly, the control system of the present invention is intended for controlling the speed of operation of an hydraulic linear actuator. It thus has particular application for controlling an hydraulic cylinder in a puller apparatus used to remove a pelt or hide from an animal carcass. For this reason, the control system of the present invention will hereinafter be described in the context of a pelt or hide puller but its end use is not limited to such applications.
Puller apparatus for removing a pelt or hide from an animal carcass is known. For example, in New Zealand patent specifications 206314 and 208963 there are described pullers for pulling or removing the pelt from sheep or other small animals. The puller apparatus as described in the aforementioned patent specifications and apparatus of this type in general usually include as. a main operative element OPEN TO PUBLIC INSPECTION UNDER SECTION 28 AND RULE 23 one or more linear actuators, eg an hydraulic cylinder or cylinders .
One problem experienced with such apparatus is pelt strain which can damage and thus reduce the value of the pelt. Pelt strain usually occurs during those periods or instances of the pulling the pelt from the carcass where there is some resistance to the clearing of the pelt over or from some part of the carcass. Due to the constant pulling force and the reluctance of the pelt to part from the carcass a damaging strain can be applied to the pelt.
One means of overcoming this problem is to reduce the speed at which the puller operates. However, economics dictate that it is not viable to operate the puller continually at a low speed.
With larger animals such as beef cattle, the removal by pulling of the hide results in extra forces being experienced when the hide is, for example, pulled over the back of the neck. This can result in breakage of the back of the animal carcass resulting in problems in boning out the carcass and damage to prime cuts of meat.
SUMMARY OF THE INVENTION There is therefore a need to be able to control the speed at which a pull is applied to a pelt or carcass at high tension points during the pulling operation to thereby overcome or at least reduce the aforementioned problems. It is an object of the present invention to provide a control system which achieves this desirable outcome.
Broadly according to one aspect of the present invention there is provided a control system for controlling the speed of operation of an hydraulic linear actuator, the system including an hydraulic accumulator means to accept hydraulic fluid diverted from a fluid line when an increased load is applied to the linear actuator and supply hydraulic fluid back to said fluid line at low load conditions.
BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic diagram of a preferred form of the control system according to the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawing linear actuator in the form of an hydraulic cylinder 10 forms part of the puller apparatus.
The piston rod P of the cylinder 10 is, in such puller apparatus, usually coupled to and drives an arm A or other operative element that forms or forms part of the pelt puller. As illustrated, arm A can move about a fulcrum F and has a clamp C or similar device at its outer or distal end for clamping with the pelt (not shown).
The hydraulic cylinder 10 is double acting being provided in a conventional manner with hydraulic lines 12 and 13 extending from a conventional directional control arrangement 11. This can be a suitable proportional valve system controlled by a P.L.C. programme. Also, in accordance with normal construction an hydraulic fluid source (not shown) is provided. Further description of such an arrangement is not required for the purposes of describing the present invention as it is well within the knowledge of the skilled person.
Extending out of hydraulic line 13 is a branch line 14 which is coupled to an hydraulic accumulator 16 via a flow control . The flow control 15 can be provided with a free return choke. However, as shown, the flow control is a standard proprietary valve system.
In accordance with conventional hydraulic accumulator construction, the accumulator 16 includes an oil reservoir 17 and a nitrogen bladder 18. The oil reservoir 17 accordingly varies in volume.
The control system according to the present invention will now be described more particularly with reference to the manner in which the system operates.
In-flow of hydraulic fluid along line 13 is constant upon leaving the directional control arrangement 11. When there is a high load demand on cylinder 10 (ie high resistance to the pelt separating from the carcass) an hydraulic fluid flow occurs via branch line 14 and flow control 15 into reservoir thereby reducing flow rate of hydraulic fluid to the cylinder 10. As a consequence, operation of the cylinder 10 slows and the rate of pull also slows thereby leading to reduction in pelt strain.
Upon the resistance being overcome the flow of hydraulic fluid to the cylinder 10 reverts to normal and the cylinder assumes its normal speed of operation.
Under low load conditions, hydraulic fluid flows out of the reservoir 17 to thereby increase the hydraulic fluid flow along line 13 into cylinder 10. This results in an increase in the rate of linear movement of the piston in cylinder 10.
Hence the rate of pelt removal is increased.
Accordingly, the present invention while using an hydraulic accumulator does not use it in its normal usage of storage of high pressure oil but rather as a means of achieving speed change depending on load on the cylinder. As described above, high load on the cylinder 10 results in low speed of operation of the cylinder while low load results in increased or high speed.
Once the pelt has been pulled from the carcass there will generally be oil stored in the accumulator 16 and this oil is used to give additional speed to the puller thereby regaining any lost cycle time.
Therefore, while slowing down of a puller to overcome the problem of strain is achieved such slowing down of the machine is only at those particular times where high tension arises and consequently reduced speed is necessary to reduce strain.
Therefore, contrary to known puller equipment operating at constant speed the present invention results in a puller when fitted with the control system to automatically reduce its pull speed at exactly the high tension point. It is envisaged that this will reduce pelt strain. Also, with, say, beef carcasses the problem of broken back can be alleviated. This, it is envisaged, will be without the need to use the known technique of electrical stimulation to re20 stiffen the back muscles of the carcass.

Claims (14)

1. A control system for controlling the speed of operation of an hydraulic linear actuator, the system including an 5 hydraulic accumulator means to accept hydraulic fluid diverted from a fluid line when an increased load is applied to the linear actuator and supply hydraulic fluid back to said fluid line at low load conditions. 10
2. The control system as claimed in claim 1 wherein the hydraulic accumulator means includes a reservoir and a bladder filed with a gas.
3. . The control system as claimed in claim 2 wherein the gas 15 is nitrogen.
4. The control system as claimed in claim 1, 2 or 3 wherein a flow control means is provided between the fluid line and the hydraulic accumulator means.
5. The control system as claimed in claim 4 wherein the flow control is a valve means.
6. The control system as claimed in claim 5 wherein the valve means includes a free return choke.
7. A puller apparatus for removal of the pelt or hide from 5 an animal carcass, the puller apparatus including a linear actuator means for engaging with a part of the pelt or hide, the engaging means being coupled to the linear actuator, a first fluid line coupled to the linear actuator, a second fluid line connected to said 10 first fluid line and coupled to an hydraulic accumulator means whereby hydraulic fluid diverted from said first fluid line along said second fluid line when an increased load is applied to the linear actuator is received by the accumulator means, hydraulic fluid in 15 the accumulator being supplied by the accumulator means back to said first fluid line upon low load conditions being experienced by the linear actuator.
8. A puller apparatus as claimed in claim 7 further 20 including control means to control the direction of movement in said second fluid line.
9. A puller apparatus as claimed in claim 8 wherein the control means is a valve.
10. A puller apparatus as claimed in any one of claims 7 to 5 9 wherein the linear actuator is a double acting cylinder coupled to a puller arm which is pivotal about a pivot axis, an end of the puller arm remote from the pivot axis having said engaging means. 10
11. A puller apparatus as claimed in claim 10 wherein the engaging means is a clamp.
12. A puller apparatus as claimed in claim 10 or 11 wherein the first fluid line extends to the linear actuator from
13. 15 a directional control means coupled to an hydraulic fluid source, there being a third fluid line extending from the linear actuator to said directional control means . 20 13. A puller apparatus as claimed in any one of claims 7 to 12 wherein the hydraulic accumulator means includes a reservoir and a gaseous containing bladder. 14 . 10 15.
14. 16 . A method of controlling the operation of an hydraulic linear actuator including upon high load conditions being experienced by the linear actuator diverting part of the flow of hydraulic fluid to the linear actuator to accumulator means and upon low load conditions being experienced by the linear actuator causing hydraulic fluid to flow to the linear actuator from the accumulator means . A control system substantially as herein described with reference to the accompanying drawing. A puller apparatus substantially as herein described with reference to the accompanying drawings.
IE980677A 1997-08-25 1998-08-14 A control system IE980677A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NZ32860297 1997-08-25

Publications (1)

Publication Number Publication Date
IE980677A1 true IE980677A1 (en) 1999-03-10

Family

ID=19926413

Family Applications (1)

Application Number Title Priority Date Filing Date
IE980677A IE980677A1 (en) 1997-08-25 1998-08-14 A control system

Country Status (3)

Country Link
AU (1) AU8002298A (en)
GB (1) GB2328721A (en)
IE (1) IE980677A1 (en)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL261563A (en) * 1960-03-01
DE4106845A1 (en) * 1991-03-04 1992-09-24 Deere & Co HYDRAULIC SYSTEM FOR CONTROLLING A POWER MOVING A CONSUMER

Also Published As

Publication number Publication date
AU8002298A (en) 1999-03-04
GB9817726D0 (en) 1998-10-14
GB2328721A (en) 1999-03-03

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Legal Events

Date Code Title Description
MM9A Patent lapsed through non-payment of renewal fee