Troubleshooting Knee Lift PFAFF 145 H3

[ethereal]

https://streamable.com/q0kbfs

https://streamable.com/k86ewd

Please see the linked videos above. (I wasnt able to attach them here as the file sizes are too big)

I have a PFAFF 145 H3 and need some assistance in troubleshooting the knee lifter. It does not seem to work at all, and I am not really sure where to start looking for problems as this is my first time encountering a machine with a knee lift. 

Any help is appreciated. Thank you in advance

[ethereal]

Coming back to this. I lifted up the machine head and brought the knee lift all the way to the left before lowering it back down. 

It now works with a good amount of pressure, however I would like to know if there is a way to make it work with less pressure? From what I have seen online of other knee lifts, it should be working in the first range of motion, where it is only working in the second range of motion as shown in the video below.

New video: https://streamable.com/7dhqp3

[Uwe]

I’d oil the knee lift bits, they look like they have friction without touching anything.

Then adjust the knee pad leg bar position so it’s very close to making contact when it’s in the normal, down position. Currently there’s too much free motion before it touches the lifting mechanism.

There’s a block that connects the angled pad leg bar to the horizontal shaft.  There are two set screws, the one on the bottom fixes the pad leg bar to the block, and the one on top other fixes the block on the horizontal shaft. You can adjust the position of that block (and thus the pad leg) on the shaft (sliding and rotating.)  Rotate the pad leg bar clock-wise on the shaft until it has just a little bit of free motion in the down position.

The arrow in the picture points to the location of the set screw you need loosen to make the adjustment. Hold the horizontal bar with your finger or pliers close to the contact position, then rotate the pad leg bar so the part with the pad is vertical. You may wish you had three hands to do this.

[ethereal]

Im a bit confused. Can you see the attached pic and let me know if im understanding all the parts you listed correctly?

[ethereal]

Any knowledge on what these srews in the back do as well?  @Uwe

[Uwe]

One more picture to complete the foot lift mechanism.

 

Your labeling of the first picture is correct.

The second picture shows the part that actually makes contact with the lift mechanism on the underside of the machine. Block #3 is just there to keep the shaft from sliding axially towards the back.

My third picture shows the foot lift details when you tilt back the machine. The roller bearing is on the original Pfaff foot lift, it’s not clear if your machine has the same. If your machine doesn’t have the roller bearing, it’s not the end of the world, just a less smooth movement. 

When you actuate the foot lift mechanism via the knee pad, the roller bearing presses against the contact surface to lift the foot.

There are two considerations here:

1. The distance between the roller bearing and the contact surface at neutral position (not pressing agains the knee pad) determines how much play your knee pad has before it starts lifting the foot.

2. When you lower the machine back down after tilting it back, you have to make sure the roller bearing ends up to the right of the part with the contact surface. If the bearing ends up to left of the part, then the roller bearing will not push against the contact surface and the knee lift will not work at all. You may have to push the knee pad to the left as you lower the machine to achieve the correct operating position.

The goal of your adjust is to get the roller bearing very close to the contact surface while the knee pad is in a good neutral position. You can either adjust the knee pad at the front , or you can adjust the roller bearing part in the back. It’s all relative, and connected.

 

 

 

Edited May 24 by Uwe

[Constabulary]

BTW - seems your machine has no oil drip pan.

[ethereal]

23 hours ago, Uwe said:

One more picture to complete the foot lift mechanism.

 

Your labeling of the first picture is correct.

The second picture shows the part that actually makes contact with the lift mechanism on the underside of the machine. Block #3 is just there to keep the shaft from sliding axially towards the back.

My third picture shows the foot lift details when you tilt back the machine. The roller bearing is on the original Pfaff foot lift, it’s not clear if your machine has the same. If your machine doesn’t have the roller bearing, it’s not the end of the world, just a less smooth movement. 

When you actuate the foot lift mechanism via the knee pad, the roller bearing presses against the contact surface to lift the foot.

There are two considerations here:

1. The distance between the roller bearing and the contact surface at neutral position (not pressing agains the knee pad) determines how much play your knee pad has before it starts lifting the foot.

2. When you lower the machine back down after tilting it back, you have to make sure the roller bearing ends up to the right of the part with the contact surface. If the bearing ends up to left of the part, then the roller bearing will not push against the contact surface and the knee lift will not work at all. You may have to push the knee pad to the left as you lower the machine to achieve the correct operating position.

The goal of your adjust is to get the roller bearing very close to the contact surface while the knee pad is in a good neutral position. You can either adjust the knee pad at the front , or you can adjust the roller bearing part in the back. It’s all relative, and connected.

 

Got it. Thank you for your help. Will touch base if I have any follow up questions. 

Edited May 25 by Northmount
Moved JLS comment out of the quoted post to make it obvious who is posting what.