Metal deforming – By relatively movable offset tool-faces – With tool motion in fixed path
Reexamination Certificate
2000-01-06
2001-04-10
Jones, David (Department: 3725)
Metal deforming
By relatively movable offset tool-faces
With tool motion in fixed path
C072S114000, C029S243525, C029S243526
Reexamination Certificate
active
06212931
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a rivet setting tool for setting blind rivet nuts, and a rotation reversal device.
2. Discussion of Relevant Art
Riveting tools for setting blind rivet nuts are known, which have a pressure medium rotary motor which, for first screwing a threaded rivet nut onto a threaded bolt of the apparatus, displaces the said bolt in right-hand rotation; and a separately operable pressure medium driven thrust device, which then in the course of the riveting process proper confers on the said bolt an axial motion for the upsetting process of the threaded rivet nut. After the end of the upsetting process, the pressure medium rotary motor is then driven so that the threaded bolt is displaced in left-hand rotation for unscrewing of the threaded nut. Such a blind rivet setting device can be gathered, for example, from German Patent DE-OS 37 01 883.
It is known from workshop practice that problems often arise in this and similar equipment in the transition from right-hand to left-hand rotation, the function of which is based on a complicated interplay between the pressure medium piston/cylinder drive, a rotation reversal device which is associated with the rotary motor, and a valve device which controls via an operating press button the supply of pressure medium to both the rotation reversal device and also the pressure medium piston/cylinder. Functional failures then appear particularly in that left-hand rotation is no longer possible, or on the contrary the pressure medium rotary motor can now be driven only in left-hand rotation.
SUMMARY OF THE INVENTION
The invention therefore has as its object to provide a rivet setting tool which avoids the above mentioned functional disadvantages of the prior art.
This object is attained by a rivet setting tool for setting blind rivet nuts, comprising a rotation reversal device including a valve slide and a slide housing that is moveable into a forward position and a rear position, a rotary motor connected to a feed spondle and having a direction of rotation that is controllable by said rotation reversal device, a pressure medium piston/cylinder device that is operable for a rivet upsetting process and confers an axial motion on a threaded bolt via said feed spindle, and a device that actuates said pressure medium piston/cylinder device and said rotation reversal device. Said rotation reversal device includes a fixing device that at least temporarily fixes the position between said valve slide and said slide housing, said fixing device engaging with said valve slide.
This object also is attained by a rotation reversal device for a rivet setting tool that sets blind rivet nuts, having: a slide housing that receives a valve slide in a central bore, said valve slide being movably arranged in said central bore, at least one annular seal forming at least one control space, and at least one coil spring that actuates said valve slide, said rotation reversal device having a fixing device that engages with said valve slide to at least temporarily fix the position between said valve slide and said slide housing.
In that a rivet setting tool for setting blind rivet nuts is provided, which has a rotation reversal device which includes a valve slide and a slide housing and which is movable into a forward and a rear position, and which is equipped with a rotary motor which is connected to a feed spindle and can be controlled by the rotation reversal device, and which has a pressure medium piston/cylinder drive, which is for the upsetting process and which confers an axial motion on a threaded bolt via the feed spindle, and which furthermore has available an actuating device by means of which both the pressure medium piston/cylinder drive and the rotation reversal device are operable, wherein the slide housing has a fixing device which engages in the valve slide such that the position between the valve slide and slide housing is held fast: the transition between the screwing on and screwing off is insured in an advantageous manner, before and after the upsetting process of the blind rivet nut to be set.
It has been found in practice to be advantageous to preferably use a latch device for the fixing device according to the invention, which engages in the valve slide in a mechanically simple manner by means of a suitable latch element, in order thus to establish the position between slide housing and valve slide.
The valve slide is arranged, displaceable longitudinally, within the rotation reversal device with radial play in a central bore of the slide housing. So that the latch device can engage on the valve slide, a preferably radially directed bore is formed in the slide housing to receive the latch device.
The latch device advantageously has a latch ball and/or a latch bolt, for latching in a latching position, arranged in the receiving bore of the latch device. If the latch ball engages in the latching position on the valve slide, a sliding transition between latching and unlatching of the fixing device or latching device is insured in a positive form in this manner.
For establishing a latching threshold, that is, a force threshold which has to be overcome to axially release the valve slide from the slide housing, the latching device furthermore includes, in a positive configuration, at least one spring which is resiliently mounted under the action of pressure against the latch ball and/or the latch bolt and presses this into a latching position.
In an advantageous development of the fixing device according to the invention, there is associated with this an adjusting screw by means of which the spring stress on the latch bolt and/or the latch ball can be adjusted. The reciprocal braking action of the fixing device of the valve slide housing on the valve slide can thereby be controlled in a simple manner.
It is furthermore advantageous that the latching device or the adjusting screw, the latch ball and/or the latch bolt, have openings and/or are surrounded by an annular space. So that pressure medium, for example compressed air, can also be supplied to the rear control chamber via the latching device.
In a further embodiment of the object of the invention, the receiving bore of the latching device preferably engages in a rear control chamber which is arranged within the central bore, and which is constituted by an annular seal engaging around the valve slide and dividing the free space present between the central bore and the valve slide into a forward and a rear control chamber.
In a continuing positive embodiment of the fixing device according to the invention, this includes engagement positions or latching positions, preferably fitted on the head of the valve slide and potentially constituted in the form of a recess; in a particularly preferred embodiment, the compressed air control openings formed in the head portion of the valve slide are used as engagement positions, and advantageously the supply of pressure medium remains insured by means of the engagement of, for example, a latch ball.
In an advantageous embodiment of the object of the invention, the pressure medium piston/cylinder device, the rotary motor, and the rotation reversal device are connected together in an integrated form. The rotary motor and the rotation reversal device are then mounted in an axially displaceable manner in the head of the rivet setting tool, so that the rotation reversal device or the slide housing can be displaced into the rear position, for example in the course of the upsetting process. The rear position means here that the rotation reversal device, or the slide housing and/or the valve slide, is displaced against the feed spindle receiver. In a particularly positive form, in the scope of the rotation reversal device, the valve slide and slide housing are arranged to be movable relative to each other, whereby the very advantageous effect is obtained that, in a wit
Jones David
MS Verwaltungs- und Patentges. mbH
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